<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>bind</title>
</head>
<body>
    <script type="text/javascript">
      function play(){
          console.log(this+'is play')
      }
      play();

      class Person {

      }
      let per =new Person();
      const newPlay = play.bind(per);
      newPlay();
    </script>
</body>
</html>